D-.alpha.-amino acids are valuable intermediates for the preparation of pharmaceutically-active substances (e.g. D-phenyl glycine and D-4-hydroxyphenyl glycine for the synthesis of penicillins and cephalosporins) or pesticides (e.g. D-valine for the synthesis of the insecticide fluvalinate. D-alanine is used in the preparation of the dietetic sweetening agent Alitam.RTM..omega ureidoalkyl-D-.alpha.-amino acids and omega-ureidoheteroalkyl-D-.alpha.-amino acids are analogs of D-citrulline. D-citrulline and D-homocitrulline are used in potent LH-RH antagonists and are therefore valuable compounds.
"Biotechnology and Bioengineering", vol. XXIII, pp. 2173-2183, (1981) teaches the preparation of various D-.alpha.-amino acids by means of the biotransformation of hydantoins appropriately substituted in the 5-position. The process is carried out in an aqueous medium with a pH of at least 6.5 in the presence of cells of the microorganism Agrobacterium radiobacter. The biotransformation is carried at atmospheric pressure. The total yield is only 60% in the case of D-4-hydroxyphenyl glycine.